A career criminal who held staff at a mental health crisis centre hostage because he was desperate to go back to prison was jailed for 10 years.

David Slack pressed a knife to the neck of employees at Liverpool Crisis House not long after trying to kill himself by swallowing all his medication.

The 45-year-old ordered staff members to lie on the floor at the Amethyst Close premises in Everton , yelling at them: “I’ve got no choice, I’m going to score and jump in the river.”

Slack also warned them, on January 21: “You’re never going to see me again,’ and told one woman who tried to reason with him: “If you’re lying, I’ll come to get you like a commando.”

The serial robber held staff prisoner in a bathroom and then frogmarched worker Gary Parle into the back garden, who later told police: “I thought he was going to hurt me.”

Today, Judge Alan Conrad gave Slack an extra five years extended licence along with his 10 year sentence, and told him: “You represent a danger to the public and a continuing danger of causing serious psychological harm. The victims’ personal statements show just how frightening the ordeal was for them.”

Liverpool Crown Court heard how Slack had 19 separate convictions for a total of 52 offences, with six year and nine year sentences respectively for crimes in Birmingham and Hull.

One week before the crisis centre siege, Slack had threatened two women workers at the counter in a Bet Fred bookies on Breck road in Anfield.

Pointing a knife at them, and brandishing a plastic bag to be filled with cash he pointed a bottle of glass cleaner, filled with green liquid, at her.